Re: [PATCH] serial: 8250: probe all 16550A variants by default
From: Vladimir Oltean
Date: Mon May 25 2020 - 14:53:10 EST
Hi Josh,
On Mon, 25 May 2020 at 20:28, Josh Triplett <josh@xxxxxxxxxxxxxxxx> wrote:
>
> On Mon, May 25, 2020 at 04:02:38PM +0300, Vladimir Oltean wrote:
> > On NXP T1040, the UART is typically detected as 16550A_FSL64. After said
> > patch, it gets detected as plain 16550A and the Linux console is
> > completely garbled and missing characters.
>
> Interesting that there's *new* powerpc hardware that needs these
> variants. I based the patch on the fact that, on x86 at least, hardware
> using these variants hasn't been made for a long time.
>
> In the hopes of preserving at least part of the benefit of the patch,
> could you please change it to `default y if !X86_64`?
>
Why don't you add CONFIG_SERIAL_8250_16550A_VARIANTS=n in x86_64_defconfig?
> > drivers/tty/serial/8250/Kconfig | 1 +
> > 1 file changed, 1 insertion(+)
> >
> > diff --git a/drivers/tty/serial/8250/Kconfig b/drivers/tty/serial/8250/Kconfig
> > index af0688156dd0..89c7ecb55619 100644
> > --- a/drivers/tty/serial/8250/Kconfig
> > +++ b/drivers/tty/serial/8250/Kconfig
> > @@ -63,6 +63,7 @@ config SERIAL_8250_PNP
> > config SERIAL_8250_16550A_VARIANTS
> > bool "Support for variants of the 16550A serial port"
> > depends on SERIAL_8250
> > + default y
> > help
> > The 8250 driver can probe for many variants of the venerable 16550A
> > serial port. Doing so takes additional time at boot.
> > --
> > 2.25.1
> >
Thanks,
-Vladimir